Background

A finding of T3 disease (extracapsular extension, positive margins, or seminal vesicle involvement) after surgery is a high risk feature for local recurrence and biochemical failure

Adjuvant radiation therapy has been demonstrated to reduce this risk in high-risk patients, and is recommended for patients with pT3 disease based on randomized evidence from the EORTC as well as other groups

The EORTC previously reported the results of this study of RT vs observation for patients with pT3 disease after radical prostatectomy, and the 10 year results are presented here

Materials and Methods

1005 patients with pT3 prostate cancer, randomized between 1992 and 2001 to immediate 60 Gy external beam RT to the surgical bed vs a wait and see (WS) approach

At the time of failure, 58% of patients in the WS group did receive salvage RT and 22% got androgen deprivation therapy (ADT)

Grade 3+ toxicity was 5.3% for XRT vs 2.5% for WS (p=0.052)

On subset analysis, age ? 70 appeared to benefit less than younger patients.

Author's Conclusions

Post-operative radiation improves local control and bPFS for pT3N0 patients after radical prostatectomy.

Based on this study, post-operative radiation does not appear to improve overall survival or distant metastases free survival for this patient population.

Clinical Implications

Patients with pT3N0 should be offered adjuvant radiation therapy given the improvement in bPFS and local control, with low grade 3+ toxicity using conventional methods, which may be even further decreased with the advances in treatment planning (IMRT, rectal balloon, fiducial placement)

The impact of immediate adjuvant radiotherapy on overall survival may have been obscured by the fact that over half of the wait and see group also received radiation

The SWOG 8794 trial did report an overall survival benefit for pT3 patients

Could this be because of patients in the SWOG observation arm, only 1/3 got RT?

Although further investigations are warranted, this study was well-designed, and provides strong data to support the use of adjuvant radiotherapy after radical prostatectomy for patients with T3 disease. Longer follow-up and further trials may eventually shed light on the impact of this treatment paradigm on overall survival.